Finding missing calculation values

Worked solution

1. 1

   Find the missing part by subtraction.

   $?=300-157$

   The whole is three hundred and one of its parts is one hundred and fifty-seven.

2. 2

   Remove one hundred, then fifty.

   $\begin{array}{rl}300-100& =200\\ 200-50& =150\end{array}$

   These are the first two parts of one hundred and fifty-seven.

3. 3

   Remove the final seven.

   $150-7=143$

   All of the known part has now been subtracted.

4. 4

   Substitute the missing number.

   $157+143=300$

   The two added parts give the required whole.

Worked solution

1. 1

   Rebuild the missing starting whole.

   $?=125+67$

   Add the removed sixty-seven to the remaining one hundred and twenty-five.

2. 2

   Add sixty, then seven.

   $\begin{array}{rl}125+60& =185\\ 185+7& =192\end{array}$

   Sixty and seven together make sixty-seven.

3. 3

   Check in the original subtraction.

   $192-67=125$

   Removing the given amount leaves the required remainder.